Referring to FIG. 15, a metal rod 61 is inserted into a railing 60, and both ends of the metal rod 61 are secured against a molding apparatus. A plastic cover 62 is then covered the surface of the metal rod through an injection molding process and both ends of the plastic cover 62 have threaded portions 621, so the railing 60 can be secured vertically at the edge of a terrace through the threaded portions 621 and the railing 60 can be used for safety concerns.
However, conventional railing structure is disadvantageous because during the manufacturing process, the metal rod 61 is disposed in the molding directly and secured only at two ends thereof, so the metal rod 61 is not secured at the center portion of the molding. Also, when the metal rod 61 is in contact with the molding, the plastic cannot cover the contacted area of the metal rod 61, which would lead to a bad product and reduce the yield. Also, two ends of the metal rods are used to secure the metal rod 61 in the molding, so the plastic cannot cover the ends as well, so the metal rod 61 is easy to be separated from the plastic 62. Therefore, there remains a need for a new and improved hand railing structure to overcome the problems stated above.